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Don  0  .    ..lot  e 
Agr.  ...    alion    Bulletin  356. 

r,    Ohio,    Feb.    11 


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SOME  PESTS  OF  O 


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OHIO   *"*** 


Agricultural  Experiment 

Station 

WOOSTER,  OHIO,  U.  S.  A.,  FEBRUARY,  1922 

BULLETIN  356 


? 


The  Bulletins  of  this  Station  are  sent  free  to  all  residents  of  the  State 
who  request  them.  When  a  change  of  address  is  desired,  both  the  old 
and  the  new  address  should  be  given.  All  correspondence  should  be 
addressed  to  EXPERIMENT  STATION,  Wooster,  Ohio. 


■        :y ;    : 

OHIO  AGRICULTURAL  EXPERIMENT  STATION 
.  *.:.-.  ."•" '.  'soa'rd  or  "control 

John  Kaiser,  President Marietta 

T.  C.  Mendenhall,    Vice-President    Ravenna 

John  F.  Cunningham Cleveland 

O.    E.   Bradfute    Xenia 

Charles  F.  Kettering   Dayton 

Benj.  F.  McCann Dayton 

Lawrence  E.  Laybourne Springfiel'1 

L.  J.  Taber,  Director  of  Agriculture Columbus 


i 


Carl  E.  Steeb,  Secretary 


STATION  STAFF 


C.  G.  Williams.  Director 


ADMINISTRATION 

The  Director,  Chief 
William  H.  Kramer,  Bursar 
W.  K.  Greenbank,  Librarian 
Clarence  M.  Baker,  B.  S.,  Editor 

AGRONOMY 

C.  G.  Williams,  Director,  Chief 

F.  A.  Welton,  M.  S.,  Associate 
J.  B.  Park,  Ph.  D.,  Associate1 

L.  E.  Thatcher,  Ph.  G.,  Assistant 
C.  A.  Patton,  Assistant 

C.  E.  Dike,  B.  S.,  Field  Assistant 
William  Holmes,  Farm  Manager 

ANIMAL  INDUSTRY 

G.  Bohstedt,  M.  S.,  Chief 

D.  C.   Kennard,  B.   S.,  Associate 
W.  L.  Robison,  M.  S  ,  Assistant 
C.  H.  Hunt,  A.  M.,  Assistant 

A.  R.  Winter,   M.   S.,  Assistant 
P.  S.  White,  B.  S.,  Assistant 

BOTANY 

A.  D.  Selby,  B.  S.,  Chief 

True  Houser,  B.  8.,  Asst.,   ( Germantown ) 

Freda  Detmers,  Ph.  D.,  Assistant 

Roy  C.  Thomas,  M.  A.,  Assistant 

M.  J.  Young,  M.  S.,  Assistant 

CHEMISTRY 

J.  W.  Ames,  M.  S.,  Chief 
C.  J.  Schollenberger,  Assistant 
Mabel  K.  Corbould,  Assistant 
Raub  H.  Simon,  A.  M.,  Assistant 
V.  H.  Morris,  A.  B.,  Assistant 

CLIMATOLOGY 

W.  H.  Alexander,  Chief  (Columbus)' 
C.  A.  Patton,  Observer 

DAIRYING 

C.  C.  Hayden,  M.   S.,  Chief 
A.  E.  Perkins,  M.  S.,  Assistant 
C.  F.  Monroe,  B.   S.(  Assistant 

ENTOMOLOGY 

H.   A.   Gossard,   M.   S..   Chief 
Herbert  Osborn,  D.  Sc,  Associate1 
J.   S.  Houser,  M.   S.  A.,  Associate 
W.  V.  Balduf,  M.  S.,  Assistant 

FORESTRY 

Edmund  Secrest,  B.  8.,  Chief 
3.  J.  Crumley,  Ph.  D.,  Assistant 
F.  W.  Dean,  B.  8.,  Assistant 
O.  A.  Alderman,  B.  8.,  Assistant 


HORTICULTURE 

J.  H.  Gourley,  M.  S.,  Chief 

W.  J.  Green,  Consulting  Horticulturist 

Paul  Thayer,  M.  S.,  Associati 

F.  H.  Ballou,  Assistant   (Newark) 

J.  B.  Keil,  Field  Assistant 

I.  P.  Leyvib,  B.   S.,   Field  Assistant 

C.  W.  Ellenwood,  Field  Assistant 

SOILS 

Chas.  E.  Thorne,  M    S.  A.,  Chief 

J.  W.  Ames,  M.  S.,  Asso.  in  soil  chemistry 

F.  E.  Bear,  Ph.  D.,  Associate1 
A.  Bonazzi,  B.  Agr.,  Assistant 

G.  W.  Conrey,  A.  M.,  Assistant1 

FARM  MANAGEMENT 

C.  W.  Montgomery,  Chief 
G.   M.   DeGroft,   Assistant 

F.  D.   Echelberry,  B.   S.,  Office  Assistant 

DISTRICT  EXPERIMENT  FARMS 

Northeastern  Test-Farm,   Strongsville 

D.  S.  KlRBY,  Foreman 

Southwestern  Test-Farm,  Germantown 
Henry  M.  Wachter,  Managi  r 

Southeastern  Test-Farm,  Carpenter 

E.  C.    Sciiwan,   Foreman 

Northwestern  Test-Farm,  Findlay 
John  A.  Sutton,  Manager 

COUNTY  EXPERIMENT  FARMS 
( Miami  Co.  Experiment  Farm,  Troy 
3  Madison  Co.  Experiment  Farm,  London 
(  H.  W.  Rogers,  Supt.,   London 

Paulding  Co.  Experiment  Farm,  Paulding 

H.  R.  Hoyt,  Supt.,  Wooster 
/  Clermont  Co.  Experiment  Farm,  Owensville 
l  Hamilton  Co.  Experiment  Farm, 
■)  Mt.  Healthy 

(  W.  E.  Weaver,  Supt.,  Mt.  Healthy 

/  Washington  Co.  Experiment  Farm,  Fleming 
\  Washington  Co.  Truck  Experiment  Farm. 
1  Marietti 

(  S.  C.  Hartman,  M.  S.(  Supt.,  Marittta 

i  Mahoning  Co.  Experiment  Farm,  Canneld 
]  Trumbull  Co.  Experiment  Farm,  Cortland 
(  J.  Paul  Markley,  Supt.,  Canfleld 

Belmont  Co.  Experiment  Farm,  St.  Clairsville 

C.  W.  Montgomery,  Acting  Supt  . 

Wooster 

STATE   FORESTS 

Waterloo  State  Forest,  Now  Marshfleld 
Dean  State  Forost,  Steece 


■In  coop.-ration  with  the  C ige  ol  Agriculture,  Ohio  SUtfl  UnWerrity,  Columbus. 

2In  cooperation  with  the  IT.  B.  Department  of  Agriculture. 


<~>V<&\  o 


M    > 


n  . 

BIOLOGY 

LIBRARY 

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:  .'.,"•- 


CONTENTS 

Page 

Sheep  Bot  Fly  53 

Sheep  Maggot  Flies  56 

Green  Bottle  Fly 

Black  Blow  Fly 

The  Sheep  Tick  60 

The  Red-Headed  Sheep  Louse   64 

The  Sheep  Foot  Louse  69 

The  Goat  Lice   71 

The  Common  Scab  Mite  71 

The  "Head  Scab  Mite   75 

The  Foot  Scab  Mite  77 

Dipping   Sheep    77 

Coal-Tar  Creosote  Dips   78 

Cresol    79 

Nicotine    79 

Lime-Sulphur   Dips 79 

(51) 


496.i40 


( 


Immersing  the  animal  completely  is  necessary  to  control  external  para- 
sites; sheep  may  be  dipped  readily  with  the 
equipment  shown. 


Animal  leaving  the  dipping  tank 


*     1    . 
*»  »       ■> 


•  *    - 


BULLETIN 


OF  THE 


Ohio  Agricultural  Experiment  Station 

Numbkr  356  Fkbruary,  1922 


SOME  PESTS  OF  OHIO  SHEEP 

DON  C.  MOTE* 

/ 

SHEEP  BOT  FLY 

Symptoms. — The  action  of  sheep  when  attacked  by  the  bot  fly 
is  familiar  to  every  farmer  and  flockmaster.  At  the  appearance  of 
the  fly,  the  sheep  shake  their  heads  and  strike  the  ground  violently 
with  their  fore  feet.  Lowering  their  noses  to  the  ground,  they  run 
away  from  the  spot  in  an  attempt  to  shake  off  or  dodge  the  fly. 
During  the  heat  of  the  day,  the  sheep  may  crowd  together  with 
their  noses  held  close  to  the  ground  or  close  under  each  other  in  an 
endeavor  apparently  to  prevent  the  fly  from  striking  them  upon  the 
nose. 

Description  of  Insect. — The  adult  fly  is  said  to  look  something 
like  an  overgrown  house  fly.  Although  larger  than  the  house  fly,  it 
is  very  difficult  to  see,  and  still  more  difficult  to  catch  when  flying. 
Notes  on  the  life  history  of  this  fly  and  its  habits  in  Ohio  are  not 
complete.  However,  the  Ohio  Station  has  in  its  parasite  collection 
specimens  of  grubs  in  various  stages  of  development,  which  throw 
some  light  upon  this  subject. 

Minute  larvae  measuring  one-sixteenth  and  five-sixteenths  of 
an  inch  in  length  were  found  in  the  nasal  cavities  of  sheep  on  Sep- 
tember 26,  1916,  at  Wooster.  Larvae  of  about  the  same  size  were 
found  crawling  up  the  nasal  passages  of  sheep  examined  at  Carpen- 
ter, Ohio,  on  November  6,  1916.  From  the  size  of  these  specimens 
it  may  be  inferred  that  the  fly  is  prevalent  and  depositing  eggs  or 
living  larvae  in  late  summer. 

The  minute  larvae  crawl  up  the  nasal  passages  to  the  frontal 
sinuses — cavities  located  between  two  plates  of  the  skull  and  lying 

*State      Entomologist,      Phoenix,      Arizona.      Formerly     Parasitologist,     Ohio     Experiment 
Station. 

(53) 


•       • 


54 


OJilO  E-XT^JRlirEST.^TVnOX:  BULLETIN  356 


one  on  each  side  of  the  median  line  of  the  head,  between  and  a  little 
above  the  eyes.  The  frontal  sinuses  communicate  with  the  nasal 
passages  but  are  separated  from  the  brain  by  a  thick,  bony  plate. 
Here  the  larvae  live  through  the  winter,  feeding  upon  the  abundant 
mucus  found  there.     In  the  spring,  about  shearing  time  or  later, 


Sheep  Bot — Oestrus  ovis  adult,  larvae,  puparium  and  young  larvae 


SOME  PESTS  OF  OHIO  SHEEP 


55 


the  larvae  crawl  down  the  nasal  passages  and  fall  to  the  ground 
where  they  pupate.  We  have  in  the  parasite  collection  nearly 
mature  larvae  collected  on  March  3  and  on  April  15.  The  former 
specimens  were  found  in  the  cavity  of  the  horn  and  probably  would 
have  matured  the  latter  part  of  April  The  latter  specimen  pro- 
bably would  have  matured  in  May. 

We  have  only  one  note  on  the  length  of  the  pupal  stage,  which, 
however,  is  incomplete.  On  March  29,  1918,  five  bot-fly  pupae  were 
received  from  Carpenter.  When  found,  in  the  manger  of  a  sheep 
pen,  they  were  in  the  larval  stage.  The  transformation  from  the 
larval  to  the  pupal  stage  took  place  during  transit  from  Carpenter 
to  Wooster,  or  within  a  period  of  3  days. 


Sinuses  of  sheep's  head  invaded  by  Oestrus  larvae.    From  Bureau  of 
Animal  Industry,  U.  S.  D.  A. 

Upon  receipt  the  pupae  were  placed  in  an  insect-rearing  cage. 
On  May  23  or  55  days  later,  the  soil  over  the  pupae  was  removed. 
Two  of  the  pupariums  were  empty.  Evidently  two  flies  had 
emerged.  A  search  revealed  a  male  and  female  in  the  folds  of  cloth 
covering  the  hole  in  one  side  of  the  cage.  Frequent  observation  of 
the  cage  failed  to  display  an  adult  fly,  so  it  was  assumed  that  none 
had  emerged.  How  long  since  these  two  had  emerged  is  of  course 
not  known.  The  flies  were  dead  when  found.  No  flies  ever 
emerged  from  the  remaining  pupal  cases.  According  to  various 
authorities  the  length  of  the  pupal  stage  varies  from  40  to  50  days, 


56 


OHIO  EXPERIMENT  STATION:  BULLETIN  356 


depending  upon  the  temperature.  Assuming  that  the  grubs  ma- 
ture in  April,  then  the  flies  would  be  present  during  May  and  per- 
haps June  and  July.  But  it  is  not  likely  that  all  the  grubs  mature 
at  the  same  time,  so  the  flies  are  probably  present  during  May, 
June,  July  and  August,  and  possibly  later.  Since  we  have  in  the 
parasite  collection  only  two  specimens  of  the  adult  flies,  reared  from 
the  grub  stage,  a  statement  of  the  seasonal  appearance  of  the  fly  in 
Ohio  cannot  be  definitely  made. 

Control. — While  the  life  stages  of  this  pest  have  long  been  de- 
scribed, its  habits  and  relative  abundance  under  different  methods 
of  flock  management  still  remain  subjects  for  investigation.  New 
and  adequate  methods  of  combating  the  sheep  bot  fly  may  result 
from  information  thus  obtained. 


Sinuses  of  sheep's  head  invaded  by  Oestrus  larvae 
From  Bureau  of  Animal  Industry,  U.  S.  D.  A. 

Remedies  now  commonly  recommended  consist  of  the  applica- 
tion of  some  repellent,  such  as  tar,  to  the  sheep's  nose  to  keep  the 
flies  away  and  trephining  to  remove  the  grubs  in  case  they  become 
injurious  to  valuable  sheep. 

SHEEP  MAGGOTS 
Symptoms  and  Injury. — The  maggots  usually  attack  the  flesli 
in  the  region  of  the  rump  or  the  horns.     They  have  hatched   from 
eggs  deposited  by  flies  attracted  to  the  wool   soiled  with   urine  or 


SOME  PESTS  OF  OHIO  SHEEP 


57 


scourings,  or  with  blood  from  slight  cuts  or  bruises  around  the 
horns  caused  by  fighting.  If  neglected,  the  infestation  continues, 
additional  flies  depositing  their  eggs  upon  the  wool  that  has  been 
rendered  more  attractive  by  its  vile  odor.  The  maggots,  working 
in  the  wool  next  to  the  skin,  some  even  in  the  flesh,  soon  loosen 
large  patches  of  the  wool.  These  patches  may  be  easily  removed  or 
they  may  even  slough  off,  exposing  a  red,  raw  maggot-infested 
flesh.  Healthy  tissue  is  soon  invaded  by  the  maggots  and  death 
may  follow,  usually  from  some  form  of  blood  poisoning,  if  the  infes- 
tation is  not  checked  immediately.  Even  if  the  animal's  life  is 
saved,  considerable  loss  of  flesh  and  wool  usually  occurs.  The  old 
adage  "An  ounce  of  prevention  is  worth  a  pound  of  cure"  is  cer- 
tainly applicable  in  combating  this  pest. 


Sheep   maggot   fly 

Phormia  regina 


Sheep   maggot  fly 

Lucilia  sericata 


The  Insects. — Two  species  of  flies  have  been  bred  by  the  Ohio 
Experiment  Station  from  maggots  infesting  the  wool  of  sheep. 
Both  are  related  through  family  ties  to  the  house  or  typhoid  fly.  A 
brief  description  and  life  history  of  each  species,  that  has  been 
identified  on  live  wool,  follow. 


GREEN  BOTTLE  FLY 

Lucilia  sericata  Meigen 


This  bright  greenish-tinted  fly  is  the  well-known  sheep  mag- 
got-fly of  the  British  Isles.     There  it  is  popularly  known  as  the 


58  OHIO  EXPERIMENT  STATION:  BULLETIN  356 

"blue  bottle"  although  it  has  more  bright  greenish  tints  than  any 
other  tint.  Like  the  house  fly,  it  is  rather  closely  associated  with 
the  habitations  of  man.  These  bright-colored  flies  are  often  very 
noticeable  in  cities,  feasting  upon  garbage,  decaying  vegetable  or 
animal  matter.  They  may  also  come  into  the  house  and  blow  ex- 
posed meat. 

The  fly  is  of  moderate  size  and  is  of  a  rich  metallic  green  color 
with  bronzy  tints  on  the  abdomen.  It  differs  from  other  species  of 
the  genus  Lucilia  in  having  the  center  of  the  dorsal  surface  of  the 
meso-thorax  furnished  with  three  pairs  of  stout  bristles,  and 
bristles  on  the  third  abdominal  segment  rather  small  and  hidden  by 
long  silken  hairs.  The  front  of  the  thorax  behind  the  head  is 
covered  with  a  fine  whitish  bloom.  These  flies  are  distinguished 
from  the  common  blow  flies  Calliphora  by  their  smaller  size,  rich 
metallic  tints  and  whitish  bloom  on  the  thorax  behind  the  head. 
The  space  in  front  of  the  head,  which  in  the  typical  blow  fly  is 
covered  with  fine  hairs,  is  bare. 

The  female  fly,  attracted  by  foul  smelling  wool,  deposits  its 
eggs  in  clusters  of  a  few  dozen  to  one  hundred  or  more.  The  eggs, 
stuck  together  with  a  secretion  that  adheres  to  the  wool,  are  pale 
yellow  and  about  one-sixteenth  of  an  inch  long.  The  life  history  of 
this  species  has  been  carefully  observed  from  the  stage  when  the 
eggs  were  found  upon  the  wool  to  that  of  the  adult  fly.  Eggs  laid 
sometime  between  10  A.  M.  and  3  P.  M.  on  September  21,  1916, 
were  collected  and  placed  in  vials.  The  eggs  in  the  different  vials 
hatched  in  9,  17  and  24  hours.  Those  hatching  first  were  kept  at  a 
warmer  temperature  (26  degrees)  C.  Of  three  vials  kept  at  the 
same  temperature,  the  eggs  in  one  hatched  in  17  hours  and  those  of 
the  remaining  two  began  hatching  in  24  hours. 

The  maggots  were  fed  upon  meat  and  in  6  days  were  mature 
and  ready  to  pupate;  in  7  days  after  pupation  the  perfect  fly 
emerged  (temperature  ranging  from  22  to  30  degrees  C).  The  fly 
thus  averages  a  life  cycle  of  about  14  days  in  warm  weather. 

The  maggot  (larva)  is  smooth  and  cylindrical,  tapering  toward 
the  head  end,  becoming  thicker  toward  the  anal  end.  The  head  is 
provided  with  a  pair  of  black,  sickle-shaped  hooks  with  which  the 
maggot  digs  into  the  flesh.  Some  of  the  rear  segments  are  fur- 
nished on  the  underside  with  rows  of  very  fine  spines  which  aid  the 
larva  in  moving.  It  moves  along  rapidly  in  its  food  material,  in  the 
wool,  or  on  the  ground.  When  mature  the  larva  generally  drops  to 
the  ground  and  contracts  into  a  form  somewhat  the  shape  of  a  bar- 
rel, called  the  pupa.    The  skin  of  the  larva  becomes  the  pupa-case, 


SOME  PESTS  OF  OHIO  SHEEP  59 

hardens  and  assumes  a  dark  brown  tint.     On  the  inside  of  this 
pupa-case  wonderful  changes  take  place,  resulting  in  a  perfect  fly. 

This  fly  probably  winters  over  in  the  pupa-case,  since  pupae 
were  found  in  the  pen,  which  contained  a  fly-blown  sheep,  under- 
neath the  bedding  in  late  October.  Larvae  placed  in  an  outside 
cage  in  late  fall  were  found  in  the  pupa  stage  in  the  early  spring. 
On  May  18,  1917,  two  adult  flies  were  taken  from  this  cage  and  one 
plump  pupa  was  found.  Later,  June  13,  an  adult  fly  emerged 
from  this  pupa-case.  On  June  17,  four  adults  flies  were  taken  from 
the  cage.  These  flies  lived  until  June  22  (5  days)  without  food  or 
water. 

BLACK  BLOW  FLY 

Phormia  regina  Meigen 

The  black  blow  fly  has  been  reared  from  larvae  working  in 
blood-stained  wool  around  the  horns  of  rams  pasturing  together. 
Thus  this  fly  differs  from  the  "blue  bottle"  in  that  it  is  attracted  to 
and  deposits  its  eggs  in  wool,  stained  from  bruises  or  minor  skin 
injuries.  The  eggs,  according  to  F.  C.  Bishopp  (Farmers'  Bul- 
letin No.  857)  hatch  in  from  less  than  24  hours  to  4  days.  From  a 
collection  of  larvae  received  from  Carpenter,  Ohio,  July  24,  1918, 
pupae  were  formed  5,  7  and  8  days  later.  Adult  flies  emerged  from 
the  pupal  cases  9  days  later.  Of  another  collection  received 
August  21,  1916,  the  pupal  stage  lasted  from  7  to  8  days.  Sum- 
marized, the  length  of  time  from  egg  to  fly  may  range  from  13  to  21 
days.  The  adult  fly  is  considerably  larger  than  the  house  fly  and 
greenish  black  in  color.  It  is  very  prolific  and  usually  becomes 
very  abundant  during  the  late  summer. 

Control. — Careful  examination  at  intervals  of  a  few  days  of 
each  member  of  the  flock  during  the  summer  and  early  fall  months 
is  recommended.  Soiled  wool  likely  to  attract  the  flies  may  be  re- 
moved or  treated  with  some  deodorant  in  order  to  counteract  the 
smell  that  attracts  the  flies.  If  sheep  are  blown,  the  infested  wool 
should  be  sheared  off,  all  the  maggots  removed  and  killed  and  the 
infested  area  rubbed  with  a  crystal  of  blue  stone  (copper  sulphate). 
The  Ohio  Station  has  found  the  copper  sulphate  treatment  very 
effective  if  used  in  the  early  stages  of  the  infestation.  It  dries  the 
infested  area  and  stops  the  decomposition  which  gives  rise  to  the 
putrid  smell  that  attracts  the  flies.  Reinfestation  is  thus  pre- 
vented. Crutching  is  recommended  and  used  in  Australia  as  a 
blow  fly  preventive. 

Sheep  infested  over  a  larger  area  are  not  so  easily  cured.  The 
infested  wool  and  all  the  maggots  should  be   removed.     To  remove 


60  OHIO  EXPERIMENT  STATION:  BULLETIN  356 

the  maggots  tunnelling  under  the  skin,  the  application  of  chloro- 
form to  the  infested  parts,  is  recommended.  Then  the  area  should 
be  dressed  with  some  mixture  that  will  repel  the  flies.  A  mixture 
consisting  of  crude  carbolic  acid,  1  part;  kerosene,  3  parts;  fish  oil, 
4  parts ;  and  oil  of  tar,  2  parts,  was  found  to  be  effective. 

To  reduce  the  chance  of  maggot-fly  attacks  measures  designed 
to  reduce  the  number  of  flies  should  be  adopted.  These  measures 
include  the  destruction  of  all  matter  in  which  the  maggots  may 
develop,  such  as  dead  carcasses,  entrails,  pieces  of  meat  and  in  fact 
every  kind  of  animal  offal.  Build  a  firewood  heap  and  then  place 
the  carcass  or  offal  on  the  heap  and  see  that  all  the  material  is  con- 
sumed. Partially-burned  animal  flesh  may  harbor  millions  of  mag- 
gots. Another  measure  to  be  recommended  when  the  flies  are 
abundant,  consists  in  half  skinning  an  animal  which  has  recently 
died  and  cutting  the  flesh.  Then  pour  over  this  carcass  a  solution 
of  1  pound  of  arsenic  dissolved  by  boiling  in  5  gallons  of  water,  and 
this  carcass  will  attract  hundreds  of  flies  which  on  sucking  the  poi- 
son die  off  in  great  numbers.  This  method  of  poisoning  adult  flies 
has  been  used  in  Australia  with  the  result  that  thousands  of  flies 
die  around  every  carcass  thus  treated  (Farmers'  Bulletin  95  by 
W.  W.  Frogratt,  Government  Entomologist,  New  South  Wales). 

The  action  of  the  arsenic  upon  the  flesh,  however,  soon  stops 
the  decomposition  and  hardens  it,  so  that  it  loses  its  attractive 
power  within  the  second  day ;  but  the  carcass  can  be  turned  over 
and  the  under  surface  will  act  as  a  poison  bait  for  another  day  if 
similarly  treated.     The  carcass  should  then  be  burned  or  buried. 

SHEEP  TICK 

Melophagus  ovintts  Linn. 

Injury. — This  parasite  lives  upon  the  blood  of  sheep  which  it 
obtains  by  sinking  its  sucking  tube  into  the  flesh.  Although  one 
tick  may  not  consume  much  blood  in  24  hours,  the  total  amount 
taken  by  a  large  number  of  ticks  constitutes  a  serious  drain  upon 
the  infested  animal.  The  irritation  caused  by  the  ticks  makes  the 
sheep  restless.  It  stamps  its  feet,  scratches  the  irritated  spot  with 
its  hind  foot,  bites  at  it  or  rubs  against  the  manger,  a  post  or  any 
other  object  within  reach.  This  continual  scratching  and  nibbing 
brings  about  a  ragged,  taggy  appearance  of  the  coat  of  wool.  The 
infested  sheep  does  not  thrive  well,  growing  or  fattening  slowly. 

During  the  winter  of  1018-19  the  Ohio  Station  conducted  a 
feeding  experiment  with  two  lots  of  lambs,  some  of  which  as  the 
winter  progressed  became    heavily   infested   with   ticks   and   lice. 


SOME  PESTS  OF  OHIO  SHEEP 


61 


The  lambs  were  weighed  individually  each  week  so  that  a  com- 
parison of  gains  made  could  be  readily  ascertained.  It  was  easy 
also  to  determine  the  relative  number  of  ticks  and  lice  infesting 
each  sheep.  It  was  found  that  the  lambs  heavily  infested  were  the 
ones  that  did  not  gain.  Table  I  shows  changes  in  weight  during  1 
week  as  well  as  the  degree  of  infestation  at  the  time.  It  will  be 
noted  that  sheep  numbers  190  and  226,  having  but  few  lice  and  no 
ticks,  made  gains  during  the  week  while  the  others  either  remained 
nearly  the  same  or  lost  in  weight.  Of  course  it  would  be  difficult  to 
determine  from  these  data  the  exact  role  played  by  ticks  and  lice 
separately  in  reducing  the  weight.  Both  parasites  finally  became 
so  abundant  as  to  interfere  with  the  object  of  the  experiment. 

TABLE  I.— COMPARISON  OF  LOSS  OR  GAIN  IN  WEIGHT  AND  DEGREE 
OF  INFESTATION  WITH  LICE  AND  TICKS 

Lot  1 


Sheep  number 

Weight  in  pounds 

Degree  of  infestation 

February  9 

February  16 

Lice 

Ticks 

190 

81.5 

46 

78.5 

95 

61 

75 

74.5 

83.5 

47 

78 

94.5 

60 

75.5 

75 

Very  few 
Very  few 
Fairly  heavy 
Fairly  heavy 
Fairly  heavy 
Fairly  heavy 
Fairly  heavy 

o 

226 

0 

185 

Fairly  heavy 
Fairly  heavy 
Fairly  heavy 

191 

209 

222 

186 

Fairly  heavy 

"Heavy  infestation"  as  used  in  the  table,  means  that  one  had 
no  difficulty  in  finding  ticks  or  lice  on  any  part  of  the  animal.  From 
the  foregoing  it  is  evident  that  the  sheep  tick  causes  a  shrinkage  in 
weight,  and  unthrifty  condition  of  the  infested  animal  and  a  rag- 
ged, taggy  coat  of  wool.  The  vitality  of  the  animal  is  also  much 
reduced  so  that  it  cannot  offer  normal  resistance  to  the  attacks  of 
other  parasites  or  diseases. 

The  tick. — The  sheep  tick  is,  according  to  entomologists,  a 
wingless  fly,  hence  it  is  in  no  way  directly  related  to  the  true  ticks. 
A  true  tick  has  in  the  adult  stage  eight  legs,  while  the  so-called 
sheep  tick  has  only  six  legs  and  in  general  form  and  structure  is 
quite  different. 

The  life  cycle  of  the  tick  is  unlike  that  of  most  of  its  kin,  the 
flies.  The  egg  and  larva  develop  within  the  female  which  finally 
deposits  her  offspring  in  the  pupal  stage.  The  pupa  is  a  hard 
shelled,  seed-like  body,  at  first  a  pale  color,  later  turning  brown. 
On  the  inside  of  the  shell  changes  are  in  progress  which  in  time  re- 
sult in  a  young  tick,  which  breaks  open  the  shell  at  one  end  and 


62  OHIO  EXPERIMENT  STATION:  BULLETIN  356 

emerges  eager  for  a  meal  of  blood.  The  time  between  the  deposit- 
ing of  the  pupa  and  the  emergence  of  the  young  tick  varies,  depend- 
ing upon  the  temperature  in  part  at  least.  This  time  has  been  var- 
iously estimated  at  from  10  to  19  days  in  summer  and  24  days  or 
even  longer  in  winter.  Young  ticks  have  been  observed  to  emerge 
from  pupae  on  the  host  animal  19  days  after  the  pupae  were  de- 
posited. When  taken  off  the  host  animal  and  kept  in  vials  young 
ticks  have  emerged  in  20,  25,  27  and  29  days  after  the  pupae  were 
collected.  The  temperature  during  this  time  ranged  from  65  de- 
grees to  80  degrees.  The  young  tick  develops  very  rapidly  reach- 
ing sexual  maturity  in  a  few  days.  The  female  deposits  her  first 
pupa  about  14  days  after  emerging  from  the  puparium  which  the 
hard  shell  is  called. 

The  longevity  of  the  young  and  adult  ticks  is  of  practical  inter- 
est, since  this  point  will  determine  how  soon  it  will  be  safe  to  turn 
sheep  dipped  for  ticks  into  pens  or  pastures  formerly  occupied  by 

infested  sheep.  Young  ticks 
have  been  observed  to  live  for  5 
days  away  from  sheep,  while 
adults  have  lived  from  4  to  7 
days.  Those  ticks  recently  en- 
gorged with  blood  generally  live 
longer  when  removed  from  sheep 
than  those  not  so  engorged. 
The  ticks  spread  from  one 
Sheep  Tick  sheep   to    another   through    con- 

Melophagus  ovinus,  adult  and        tact  both   with  infested   sheep  or 
puparium  with  tagg  Qf    wqq]    {rQm    infested 

sheep.  During  cold  weather  when  sheep  are  placed  in  sheds  in 
close  contact  the  conditions  are  favorable  for  a  rapid  spread  of  the 
ticks.  They  pass  readily  from  one  sheep  to  another,  especially 
from  the  ewe  to  her  lamb. 

Control. — The  points  of  practical  interest  then  in  the  life  his- 
tory and  habits  of  the  tick  bearing  on  its  control  are: — (1)  length 
of  pupal  stage,  generally  19  to  24  days;  (2)  period  before  female 
deposits  her  first  puparium,  about  14  days;  (3)  longevity  of  tick 
when  removed  from  host,  4  to  7  days ;  the  pupae  of  course  when  re- 
moved would  hatch  out  in  19  to  24  days  or  even  longer  into  ticks 
capable  of  reinfesting  animals ;  (4)  the  ticks  pass  readily  from 
infested  animals  to  other  animals.  There  is  even  danger  of  the  at- 
tendants spreading  them.  Ticks  have  been  found  upon  the  trous- 
ers of  attendants  several  hours  after  the  handling    of  infested 


SOME  PESTS  OF  OHIO  SHEEP  63 

sheep.  Since  the  sheep  tick  remains  upon  the  animal  during  its 
entire  life  cycle  it  will  be  necessary  in  order  to  combat  it  to  use 
some  substance  upon  the  animal  that  will  kill  the  ticks  and  still  not 
injure  the  sheep  or  its  fleece. 

Dipping  or  immersing  the  infested  sheep  in  a  liquid  that  will 
kill  the  ticks  is  the  most  practicable  method  known  for  eradication. 
The  dips  generally  recommended  for  this  purpose  are  those  contain- 
ing arsenic  or  nicotine  as  the  active  principle,  and  the  coal-tar  or 
cresylic  acid  dips.  These  dips  are  manufactured  and  sold  for  this 
purpose  and  care  should  be  exercised  to  follow  closely  the  directions 
supplied  by  the  manufacturer.  Under  no  consideration  should  one 
attempt  to  make  and  use  a  home-made  arsenic  dip  without  reliable 
instructions  and  guidance.  One  sheep  owner  attempted  this  and 
lost  a  considerable  number  of  sheep  out  of  his  flock  and  nearly 
poisoned  himself.  If  after  following  the  directions  closely  the  dip 
used  does  not  eradicate  the  ticks,  notify  the  Ohio  Agricultural  Ex- 
periment Station,  Wooster,  or  the  Federal  Insecticide  Board,  Wash- 
ington, D.  C. 

From  10  days  to  2  weeks  after  shearing  is  generally  considered 
the  best  time  for  dipping,  as  the  shear  cuts  are  then  generally 
healed.  It  is  dangerous  to  dip  sheep  in  some  of  the  dipping  pre- 
parations if  there  are  any  fresh  wounds  upon  the  animals.  How- 
ever, sheep  may  be  dipped  at  any  other  time  during  the  summer  or 
early  fall  if  they  are  found  to  be  infested.  Even  during  the  win- 
ter, according  to  some  authorities,  they  may  be  dipped  with  reason- 
able safety  if  the  dipping  for  the  day  is  finished  by  noon  so  that  the 
flock  may  have  time  to  dry  off  and  fill  up  with  feed  before  night. 
Others  state  that  dipping  in  the  winter  is  too  severe  and  should  not 
be  practiced. 

The  problem  of  safely  and  effectively  combating  the  tick  in 
winter  is  yet  unsolved.  Spotting,  or  pouring  the  liquid  along  the 
back  and  allowing  it  to  run  down  into  the  wool  is  sometimes  re- 
serted  to.  This  remedy,  however,  should  not  be  considered  as  final, 
for  at  best  it  kills  only  a  few  of  the  ticks.  The  infested  flock  will 
have  to  be  dipped  in  the  spring.  The  use  of  an  insecticide  powder 
suggests  itself  since  this  form  of  treatment  has  been  very  effective 
against  external  parasites  upon  other  animals 

During  the  winter  of  1917  the  Ohio  Experiment  Station  con- 
ducted an  experiment  to  test  the  effectiveness  of  pyrethum  and  the 
Cornell  (Lawry)  powder  as  a  remedy  for  ticks.  The  powder  was 
applied  by  means  of  a  shaker  made  by  punching  holes  in  the  lid  of  a 
tin  can.     The  wool  was  spread  apart  by  the  person  holding  the 


64 


OHIO  EXPERIMENT  STATION:  BULLETIN  356 


sheep  while  an  assistant  handled  the  shaker.  It  took  about  10 
minutes  to  dust  one  sheep.  Each  sheep  was  thoroughly  dusted  on 
head,  neck,  back,  rump,  legs  and  abdomen. 

TABLE  II.— DATA  AND  RESULTS  OF  THE  DUSTING 


Sheep  number 

Powder  u^ei\ 

Ticks  before 
dusting 

Live  ticks  7  days  after  dusting: 

Dozen 

Adults 

Young 

163 

Cornell  (Lawry 

Cornell  (Lawry) 

Cornell  (Lawry) 

Cornell  (Lawry) 

Pyrethrum 

Pyrethrum 

Pyrethrum 

Pyrethrum 

Pyrethrum 

Pyrethrum 

3 
1+ 

6 

3 

1 

1 

2 

6 

3+ 

1 

1 

1 

1 

0 

0 

6* 

0 

0 

ot 

0 

0 

169 

2 

168 

o 

175 

o 

165 

o 

172* 

173 

o 

176 

o 

164t 

o 

166 

o 

*A  very  close-wooled  animal. 

tSome  of  the  pupae  gathered  from  this  animal  hatched  out  in  from   10  to   14  days. 

It  will  be  noted  that  pyrethum  seemed  to  be  more  effective 
than  the  Cornell  (Lawry)  powder.  However,  neither  one  killed  all 
the  ticks  and  a  second  and  perhaps  a  third  dusting  would  be  neces- 
sary to  get  those  that  escaped  or  hatched  out  after  the  first  dusting. 
Dusting  sheep  is  a  tedious  operation  and  could  hardly  be  attempted 
except  upon  a  small  flock.  And  even  then  dipping  should  be  re- 
sorted to  in  spring  to  eradicate  those  that  escaped. 

The  feeding  of  sulphur  to  animals  to  rid  them  of  their  external 
parasites  is  often  recommended  by  some  well-meaning  correspond- 
ent of  the  agricultural  press.  To  test  this  method  two  lots  each  of 
16  ewes,  all  tick-infested,  were  given  free  access  to  a  mixture  of  1 
pound  of  sulphur  and  2  pounds  of  salt.  Each  lot  received  3  pounds 
of  the  mixture.  In  2  weeks  time  they  had  consumed  the  mixture. 
An  examination  of  the  ewes  revealed  more  ticks  than  before  the 
test  began.  Fumigation  gives  promise  of  being  an  effective  rem- 
edy for  external  parasites  of  animals  and  in  time  a  practical  method 
may  be  evolved  for  eradicating  these  pests  by  this  means.  It  is  in- 
teresting in  this  connection  to  note  that  soldiers  suffering  from  itch 
or  scabies  found  themselves  cured  after  exposure  to  chlorine  gas, 
which  was  largely  employed  by  the  Germans  in  gas  attacks  during 
the  war. 

RED-HEADED  SHEEP  LOUSE 
Ttiokodtettt  sphaooci tphahu 

Symptoms. — Lousy  sheep  may  be  observed  rubbing  them- 
selves against  the  feed  rack,  posts,  corners  of  the  sheep  pen  or 
other  stationary  objects  in  order  to  relieve  themselves  of  the  itch- 


SOME  PESTS  OF  OHIO  SHEEP  65 

ing  sensation  produced  by  lice.  Frequently  they  scratch  the  in- 
fested parts  with  their  hind  feet  or  bite  at  the  region  infested. 
Not  only  do  the  bites  and  sharp  claws  of  the  lice  annoy  the  sheep 
but  they  also  affect  the  smooth  pink  skin.  Animals  heavily  in- 
fested with  these  pests  have  a  roughened  dry  skin  covered  with 
little  dry  brownish  scabs.  The  wool  fibers  become  loose,  probably 
due  to  the  cutting  operations  of  the  mandibles  of  the  insects.  Then 
by  continued  scratching  and  gnawing  the  infested  sheep  causes  the 
wool  to  become  ragged,  short,  dry,  gnarly  and  worthless. 

Description  of  Louse. — The  little  red-headed  sheep  louse  is  so 
small  that  it  may  easily  escape  detection.  It  is  slightly  longer  than 
1-25  of  an  inch.  It  is  of  a  pale  brownish  color  and  possesses  a  red- 
dish head.  It  commonly  lives 
near  the  skin  on  the  upper  parts 
of  the  neck,  shoulders,  back  and 
thigh,  though  it  may  be  found  on 
any  part  of  the  fleece.  Coarse- 
wooled  sheep  seem  to  be  more 
frequently  infested.  It  is  prob- 
able that  sheep  can  only  become 
infested  by  rubbing  against  other  11 
infested  sheep  or  objects  which  fe~L, 
these  have   rubbed   against.     No  %£ 

other  host  of  this  louse  is  as  yet  Sheep  Louse,  Trichodectes 

known.     This  louse  was  collected     sphaerocephalus,  adult  and  egg, 
at  Wooster,   Ohio,   November  24,  greatly  enIarged 

1917,  and  specimens  have  been  received  from  Ft.  Recovery,  Ohio, 
taken  November  21,  1917,  and  West  Cairo,  Ohio,  January  8,  1917. 
The  life  history  of  this  louse  is  similar  to  that  of  other  lice.  The 
tiny,  pale,  white  "nits"  are  glued  to  the  wool  fibers.  Young  lice, 
similar  except  in  size  to  the  adults,  emerge  in  a  short  time  from  the 
free  ends  of  the  "nits".  The  young  shed  their  skin  several  times 
and  finally  reach  maturity. 

Control  measures. — The  sheep  louse  may  be  effectively  com- 
bated at  the  same  time  and  with  the  same  dips  as  are  recommended 
for  the  sheep  tick.  In  the  winter,  however,  dipping  is  not  advis- 
able. Among  the  winter  remedies  that  have  been  suggested  may 
be  mentioned  fumigation  and  powder  insecticide.  Of  the  powder 
insecticides  sodium  fluorid  gives  the  most  promise.  Sodium  flu- 
orid  is  a  salt  belonging  to  the  same  group  as  sodium  chloride  or 
table  salt.  It  has  recently  been  demonstrated  by  Bishopp  of  the 
Bureau  of  Entomology  to  be  100  percent  efficient  in  combating 


66 


OHIO  EXPERIMENT  STATION:  BULLETIN  356 


chicken  lice.  Prior  to  this  work  its  only  known  insecticidal  use  was 
against  cockroaches,  for  which  it  has  been  demonstrated  to  be  high- 
ly effective. 

In  December,  the  flockmaster  at  the  Ohio  Agricultural  Experi- 
ment Station  reported  that  the  ewes  were  rubbing  themselves  and 
pulling  out  their  wool.  An  examination  of  the  taggiest  of  the  ewes 
showed  a  heavy  infestation  of  red-headed  lice  to  be  the  cause  of  the 
unrest.  As  these  ewes  had  been  dipped  2  years  before,  the  lice 
probably  had  been  introduced  into  the  flock  by  an  imported  ram. 
The  importance  of  using  protective  measures  in  the  case  of  every 
new  addition  from  outside  sources  in  therefore  emphasized. 


Dusting  a  sheep  with  a  plunger  gun. 

There  were  102  ewes  in  the  flock.  To  treat  each  of  them  with 
powder  seemed  an  endless  operation.  However,  it  was  necessary 
to  check  the  ravages  of  the  lice.     So  sodium  fluorid  was  tested  on  a 


SOME  PESTS  OF  OHIO  SHEEP 


67 


small  scale,  using  three  of  the  ewes  most  heavily  infested.  On  two 
of  these  the  powder  was  blown  into  the  wool  near  the  skin.  On  the 
one,  the  powder  was  dusted  over  the  surface  of  the  wool.  As  so- 
dium fluorid  is  a  heavy  salt  it  was  thought  the  powder  would  settle 
into  the  wool.  A  later  examination  showed  that  this  method  was 
not  effective. 

The  trial  test,  however,  proved  satisfactory.  So  the  entire 
flock  of  104  ewes  was  treated.  It  was  not  possible  to  treat  all  of 
them  in  1  day  but  the  work  was  done  on  separate  days  whenever 
the  time  could  be  spared.  Two  men  were  required  for  the  opera- 
tion, one  to  hold  the  animal  and  spread  open  the  wool,  the  other  to 
operate  the  powder  gun. 


Ewe  infested  with  Lice 

Two  types  of  hand  powder  guns  were  used  in  the  test.  One 
was  of  the  ordinary  barrel  and  plunger  type ;  the  other,  the  rotating 
fan  type.  The  latter  type  makes  considerable  noise  which  tends  to 
frighten  the  animals.  The  intermittent  operation  of  the  rotary 
fan  generally  necessary  in  dusting  a  sheep  was  not  conducive  to  a 
uniform  dust  spray  when  this  type  of  gun  was  used.  The  ordinary 
barrel  and  plunger  gun  gave  the  most  efficient  service. 

The  time  factor  is  an  important  point  in  the  treatment  for  ex- 
ternal parasites.  When  everything  is  in  readiness  the  treatment 
of  sheep  parasites  by  dipping  requires  only  about  2  minutes  per 


68 


OHIO  EXPERIMENT  STATION:  BULLETIN  356 


animal.  Therefore  dusting  is  not  as  expeditious  as  is  dipping; 
however,  after  a  little  experience  the  sheep  can  be  dusted  at  the 
rate  of  one  in  every  10  to  15  minutes.  This  can  be  readily  accom- 
plished if  the  man  opening  the  wool  moves  his  hand  along  with 
sufficient  rapidity  to  maintain  a  constant  operation  of  the  gun  and 
a  uniform  spray  of  dust. 

The  amount  of  material  used  is  another  important  item  and 
materially  effects  the  cost  of  the  operation.  In  the  treatment  of 
the  104  ewes  only  5  pounds  of  sodium  fluorid  was  used.  At  this 
rate  it  would  take  only  about  six-tenths  of  an  ounce  to  one  sheep. 
Thus  at  50  cents  per  pound  (the  price  paid  for  the  material)  the  ex- 
pense for  the  salt  would  average  less  than  2  cents  per  sheep. 


Louse  in  sheep's  wool. 

While  the  statement  cannot  be  made  that  one  dusting  with 
sodium  fluorid  is  a  completely  effective  remedy  for  sheep  lice,  yet 
the  salt  may  be  used  in  winter  to  check  their  ravages  until  warmer 
weather  when  sheep  may  be  safely  dipped.  Two  days  after  the 
sheep  were  treated  we  found  a  half-dozen  lice  on  a  few  of  the  sheep 
examined.  Bishopp  states  that  the  action  of  sodium  fluorid  when 
applied  in  dust  form  on  poultry  is  comparatively  slow,  hence  if  an 
examination  is  made  the  day  following  or  even  2  or  3  days  later, 
some  lice  may  be  found ;  but  the  action  of  the  powder  persists,  and 
after  4  or  5  days  all  lice  disappear.     However  complete  oxtermina- 


SOME  PESTS  OF  OHIO  SHEEP  69 

tion  of  lice  did  not  result  from  this  test.  Twenty-five  days  after 
treatment  seven  lice  were  found  on  three  out  of  fifteen  sheep  ex- 
amined.    On  most  of  the  fifteen  many  dead  lice  were  found. 

Sodium  fluorid  appears  to  be  very  destructive  to  lice  without 
producing  any  ill  effects  upon  the  host  animals.  No  skin  irritation 
or  injury  to  the  condition  of  the  wool  was  observed.  In  dusting 
there  was  occasionally  some  temporary  irritation  of  the  air  pass- 
ages, as  evidenced  by  sneezing. 

It  is  said  that  if  some  of  the  sodium  fluorid  in  the  dust  f  orm 
reaches  the  body  of  the  operator  and  if  allowed  to  remain  for  a 
number  of  hours,  as  might  be  the  case  in  dusting  many  animals, 
local  irritation  and  burning  may  occur  on  tender  portions  of  the 
skin.  This  effect  was  not  experienced  by  the  writer  nor  helpers. 
No  special  precaution  was  taken,  but  winter  clothing  and  extra 
overalls  may  have  afforded  the  necessary  protection.  During  the 
operation  some  dust  floats  in  the  air  which  causes  irritation  of  the 
throat  and  nose  of  the  operator.  This,  although  it  caused  con- 
siderable sneezing,  proved  only  an  incidental  inconvenience.  It 
may  be  prevented  by  keeping  pieces  of  wet  cloth  over  the  nostrils 
and  mouth,  or  by  the  use  of  a  dust  guard. 

Summary. — Dipping  with  an  effective  liquid  parasiticide  is  the 
most  satisfactory  remedy  for  external  parasites. 

Dipping  is  not  advisable  in  the  winter. 

Powder  insecticides  give  promise  of  being  satisfactory  for 
winter  use. 

Sodium  fluorid  was  used  in  a  test  conducted  at  the  Ohio  Agri- 
cultural Experiment  Station;  104  sheep  were  used  in  the  test. 
The  powder  was  blown  into  the  wool  by  means  of  a  hand  powder 
gun. 

The  barrel  and  plunger  type  of  powder  gun  proved  the  more 
satisfactory.  From  10  to  15  minutes  was  required  to  treat  each 
sheep  using  about  six-tenths  of  an  ounce  of  powder  to  each  animal 
treated. 

Sodium  fluorid  kills  the  lice  without  producing  a  detrimental 
effect  upon  host  animals  or  operator. 

SHEEP  FOOT  LOUSE 

Haematopinus  pedalis  Osborn 

Injury. — This  louse  differs  from  the  other  lice  of  sheep  and 
goats  in  size,  shape  and  character  of  the  mouth  parts.  The  latter 
are  adapted  for  piercing  the  skin  and  sucking  the  blood  of  the  host 
animal ;  hence,  should  the  lice  occur  in  abundance  upon  an  animal, 
the  injury  no  doubt  would  be  more  severe  than  that  due  to  lice  that 
do  not  puncture  the  skin. 


70 


OHIO  EXPERIMENT  STATION:  BULLETIN  356 


Description  of  Louse. — The  louse  has  about  the  same  general 
shape  as  the  short-nosed  ox  louse,  though  it  is  scarcely  as  broad  and 
is  slightly  smaller.  The  darker  portions  of  the  body  being  more 
restricted  give  it  a  more  immature  look  than  the  cattle  louse.  Pro- 
fessor Herbert  Osborn  first  found  this  louse  attacking  the  legs  of 
sheep  at  Ames,  Iowa,  in  1896.  So  far  as  all  examinations  indicate 
this  louse  confines  its  operations  to  the  legs  and  feet  below  where 
the  wool  is  found.  It  is  especially  common  to  the  region  of  the 
"dew  claws"  where  the  eggs  appear  to  be  most  commonly  deposited. 
These  are  attached  to  the  hair  near  the  skin.  This  louse  has  since 
been  recorded  from  Virginia  and  Colorado.  As  yet,  no  specimens 
have  been  taken  in  Ohio. 


Sheep  foot  louse — after  Osborn.     Bui.  5,  Division  of  Entomology, 

U.  S.  D.  A.    Haematopinus  pedalis:  a,  adult  female;  6, 

ventral  view  of  terminal   segments  of  same, 

showing  brushes;  c,  terminal  segments 

of  male;  d,  egg, — all  enlarged. 

Control. — The  restricted  distribution  of  this  pest  upon  the  host 
animal  should  make  it  an  easy  matter  to  treat  the  parasite  at  any 
season  of  the  year.  The  feet  and  legs  can  be  washed  with  any  of 
the  effective  dipping  solutions,  or  the  sheep  may  be  driven  into  a 
shallow  vat  containing  enough  of  the  solution  to  reach  up  to  the 
body  without  wetting  the  wool.  Dipping  at  shearing  time  for 
"keds"  or  ticks  and  biting  lice  will  destroy  this  blood-sucking  louse 
also. 


SOME  PESTS  OF  OHIO  SHEEP  71 

GOAT  LICE* 

Symptoms. — These  lice  are  said  to  be  found  more  commonly 
upon  goats  than  the  red-headed  louse  is  found  upon  sheep.  They 
produce  a  pruritis  causing  the  infested  animal  to  scratch  and  rub 
itself  which  action  aids  in  producing  a  scabby  skin  and  loss  of 
fleece.  A  heavily-infested  animal  lacks  energy  and  finally  becomes 
poor  and  thin. 

Description  of  Louse. — Two  species  of  biting  lice  are  found  up- 
on goats,  both  of  which  are  commonly  referred  to  as  goat  lice.  The 
common  goat  louse  (see  name)  appears  to  be  the  more  abundant. 
This  species  was  collected  at  Wooster,  Ohio,  from  an 
Angora  goat  on  June  14,  1914.  This  louse  commonly 
resides  among  the  coarse  hairs  along  the  back  and 
sides.  It  is  slightly  longer  than  one-twenty-fifth  of 
an  inch,  with  brownish  head  and  thorax,  pale  yellow 
abdomen  with  dark  lateral  bands  and  median  spot  on 
each  segment.  The  head  is  more  of  a  quadrangular 
shape  than  is  that  of  the  red-headed  sheep  louse. 
The  Angora  goat  louse  no  doubt  appears  in   Ohio  but 

no  specimens  have  been  collected,  or  received  by  the 
Goat    Louse,  .■* 

Trichodectes      Ohio  Station. 

climax  Control. — The  lice  may  be  combated  by  dipping 

or  by  the  use  of  an  insecticide  powder  (see  control  of  sheep  lice),  or 
by  use  of  an  ointment  applied  to  the  infested  parts.  Dipping  is  the 
most  effective  means  of  combating  these  lice. 

COMMON  SCAB  MITE 

Psoroptes  communis  var.  ovis 

Symptoms. — This  parasite  is  one  of  the  most  widely  adver- 
tised of  sheep  parasites  by  reason  of  the  vigorous  efforts  of  the 
Federal  and  State  Governments  to  eradicate  it. 

The  mites  are  readily  transmitted  from  one  sheep  to  another. 
This  may  be  done  by  contact  with  an  infested  sheep,  by  racks 
against  which  it  has  rubbed  or  from  tags  of  wool,  pastures  or  other 
places  where  a  host  animal  may  have  been.  The  mites  seem  to 
multiply  and  spread  more  rapidly  in  the  colder  months  of  the  year. 

The  tiny  mites,  once  introduced  into  the  wool,  prick  the  skin 
and  apparently  introduce  some  irritating  substances,  for  an  itching 
sensation  soon  manifests  itself.  The  sheep  bite  at  the  infested 
region,  scratch  it  with  their  hind  feet  or  against  some  stationary 
object.     The  skin  becomes  inflamed  or  reddened  and  small  pimples 

*Trichodectes  climax  (common  goat  louse).  *Trichodectes  limbatus  (Angora  goat 
louse).  *These  lice  do  not  seem  to  be  found  on  sheep  but  are  noticed  here  because  the  goat 
is  not  an  uncommon  animal  in  Ohio. 


72 


OHIO  EXPERIMENT  STATION:  BULLETIN  356 


r— -      •  ■    '  ■    ■         — 


Life  stages  of  the  common  scab  mite 


SOME  PESTS  OF  OHIO  SHEEP 


73 


are  formed.  As  the  mites  multiply  the  area  of  the  infested  regions 
increases  and  the  itching  becomes  more  and  more  aggravating. 
The  pimples  break  and  serum  oozes  to  the  surface  of  the  skin. 
This  material  becomes  mixed  with  the  natural  secretions  and  dirt 
and  soon  hardens  into  crusts  or  scabs.  The  skin  in  the  infested 
areas  becomes  hard  and  thick.  This  may  be  readily  detected  by 
pinching  up  a  portion  and  comparing  it  with  the  surrounding 
healthy  skin.  Constant  biting,  rubbing  and  scratching  of  the  in- 
fested region  soon  causes  the  fleece  to  assume  a  condition  commonly 
known  as  "broken".  It  becomes  discolored,  worn  and  ragged. 
Large  areas  of  the  skin  become  entirely  denuded  of  wool  as  shown 
on  page  74.  Unless  properly  treated  the  disease  may  spread  over 
the  entire  body,  the  sheep  becoming  more  and  more  debilitated 
until  it  finally  succumbs.  Only  a  few  have  been  known  to  recover 
spontaneously. 


A  slightly  advanced  case  of  common  scab. 
From  Bui.  No.  21,  Bureau  of  Animal  Industry,  U.  S.  D.  A. 


74 


OHIO  EXPERIMENT  STATION:  BULLETIN  356 


Description  of  Mite. — The  mites  although  small — the  male 
may  attain  a  length  of  one-fortieth  of  an  inch,  the  female  one- 
thirty-fifth  of  an  inch — are  readily  visible  to  the  naked  eye  of  an 
experienced  observer.  They  may  be  found  on  any  part  of  the  body 
covered  by  the  wool,  but  are  most  commonly  found  where  the  wool 
is  thickest.  According  to  Gerlach,  the  female  deposits  its  eggs  in 
clumps  of  the  skin  at  the  base  of  the  wool  fibers.  Each  female  gen- 
erally deposits  not  less  than  fifteen  eggs,  which  hatch  after  an  in- 
cubation of  3  or  4  days.  The  young  mites  grow  to  maturity  in  7  or 
8  days  and  in  3  or  4  days  more  mate  and  start  the  cycle  over  again. 


A  more  advanced  case  of  common  scab. 
From  Bui.  No.  21,  Bureau  of  Animal  Industry,  U.  S.  D.  A. 

Control. — Certain  points  in  the  life  history  of  the  scab  mite 
have  an  important  bearing  upon  the  method  of  combating  this  par- 
asite. The  complete  destruction  of  the  scab  mites  is  necessary  in 
order  to  cure  the  disease  that  they  produce.  The  eggs  of  the  scab 
mite  seem  to  be  especially  tenacious.  It  is,  therefore,  necessary  to 
dip  a  second  time  after  the  eggs  have  hatched,  but  before  the  young 
have  become  sufficiently  mature  to  deposit  eggs  again.  From  the 
data  on  the  life  history,  10  to  14  days  after  the  first  dipping  has 
been  determined  as  the  best  time  for  the  second  dipping. 

The  vitality  of  the  scab  mite  when  separated  from  the  host 
animal  is  also  of  practical  importance.  Since  the  mites  and  eggs 
may  be  scattered  here  and  there  in  sheds,  or  pastures,  on  tags  of 
wool  and  loosened  scabs,  it  is  necessary  to  know  how  long  they  will 


SOME  PESTS  OF  OHIO  SHEEP 


75 


live  under  these  conditions  in  order  to  make  recommendations  con- 
cerning the  use  of  such  sheds  and  pastures.  Various  authorities 
place  the  length  of  life  of  the  mites  when  removed  from  the  body  of 
the  host  at  from  2  weeks  to  as  many  months.  Pastures  may  be 
safely  occupied  at  an  earlier  date  than  buildings  and  pens.  Two 
months  may  safely  free  open  pasture,  but  it  is  thought  that  a  much 
longer  time  should  elapse  before  healthy  sheep  are  introduced  into 
once-infested  buildings.  In  fact,  the  safest  plan  consists  in  a  re- 
moval of  all  the  bedding  and  loose  material  of  the  sheds  to  land  that 
is  to  be  plowed  and  thoroughly  spraying  the  walls,  floors  and  racks 
with  a  slightly  stronger  solution  of  the  dip  than  is  used  on  the 
sheep. 


An  advanced  case  of  common  scab. 
From  Bui.  No.  21,  Bureau  of  Animal  Industry,  U.  S.  D.  A. 

HEAD  SCAB  MITE 

Symptoms. — This  tiny  mite  confines  its  attacks  almost  ex- 
clusively to  the  parts  which  are  not  covered  with  wool.  Its  pres- 
ence is  usually  first  observed  on  the  lips,  in  the  vicinity  of  the 
angles  of  the  mouth  and  on  the  edges  of  the  nasal  openings ;  more 
rarely  it  may  show  itself  first  around  the  eyes  and  ears.  The 
mites  penetrating  into  the  skin  cause  little  watery  pimples  to  arise 
at  the  point  of  attack.  The  itching  appears  to  be  intense,  for  the 
animals  rub  the  infested  portions  vigorously  against  the  rack,  on 


76 


OHIO  EXPERIMENT  STATION:  BULLETIN  356 


the  ground,  on  their  fore  legs  or  against  other  sheep.  The  small 
pimples  break  and  a  watery  fluid  runs  out  which  on  drying  forms  a 
small  crust.  Repeated  scratching  aids  in  spreading  the  infection 
and  increasing  the  inflamation.  The  little  brownish-yellow  scabs  in 
time  become  larger,  thicker  and  may  even  cover  the  entire  face  if 
treatment  is  not  applied. 


A  shorn  sheep  with  large  bare  area  due  to  scab. 
From  Bui.  No.  21,  Bureau  of  Animal  Industry,  U.  S.  D.  A. 

Description  of  mites. — All  stages  of  this  parasite,  eggs,  young 
and  adult  males  and  females,  may  be  found  in  the  moist  layer 
underneath  the  scabs.  The  adults  are  just  visible  to  the  naked  eye 
of  the  trained  observer,  being  about  220  to  440  micromillimeters 
long.  The  minute,  oval  egg  is  deposited  by  the  female  in  the  bur- 
rows which  she  makes  by  means  of  her  mandibles.  One  female  as 
she  progresses  in  her  burrow  may  leave  behind  her  a  row  of  from 
10  to  40  eggs.  The  young,  on  hatching,  spread  to  healthy  tissue, 
beginning  burrows  of  their  own.  Thus  the  mites  spread  the  infes- 
tation over  the  face  and  to  other  sheep,  should  the  infested  sheep 
come  in  contact  with  healthy  animals.     This  mite  has  been  known 


SOME  PESTS  OF  OHIO  SHEEP  77 

to  attack  goats,  dogs  and  in  rare  cases,  man.  There  is  also  a  var- 
iety of  mite  closely  resembling  the  head  scab  mite  of  sheep  which 
commonly  attacks  goats.  This  latter  variety  has  been  found  to  at- 
tack sheep,  cattle,  horses,  swine  and  even  man. 

Control. — In  the  early  stages  of  the  infection  an  application  of 
any  of  the  dips  recommended  for  common  sheep  scab  may  be  ap- 
plied directly  to  the  infested  parts.  However,  after  the  formation 
of  the  crusts,  it  is  advisable  to  soften  them  by  the  use  of  oil  or 
grease,  and  later  to  remove  the  scabs  through  the  use  of  water  and 
alkali  soap.  Then  apply  any  one  of  the  following : — the  lime  and 
sulphur  dip,  the  tobacco  dip,  oil  of  cade,  or  Helmerich  pomade 
which  is  made  as  follows : — 

Sublime  or  precipitated  sulphur  10  grams 

Potassium  carbonate  5  grams 

Vaseline  40  grams 

FOOT  SCAB  MITE 

Symptoms. — This  mite  confines  its  attacks  to  the  feet  and 
limbs.  The  mites  spread  very  slowly  from  the  first  point  of  attack, 
commonly  the  hind  fetlocks,  and  ascend  little  by  little  the  upper 
part  of  the  legs,  rarely  passing  beyond  the  thighs.  In  infections  of 
long  standing,  however,  they  may  invade  the  inner  sides  of  the 
thighs,  the  udder  and  the  scrotum  and  in  rare  cases  the  front  legs. 
Early  in  the  infestation  the  skin  becomes  inflamed  and  covered 
with  fine  small  scales,  and  later  with  yellowish  white  crusts.  The 
infested  animals  stamp  their  feet,  scratch  and  gnaw  at  the  infested 
parts  which  action  aids  in  producing  sores  and  scabs.  As  the  mites 
multiply  the  yellowish-white  crusts  increase  and  become  thicker, 
and  a  later  stage  is  reached  in  which  the  skin  cracks. 

Description  of  Mites. — Under  the  crusts  the  parasites  may  be 
found  in  abundance,  but  in  order  to  readily  detect  them  a  magnify- 
ing glass  is  necessary,  for  the  mite  only  measures  310  to  400  micro- 
millimeters  by  250  to  260  micromillimeters.  The  mite  lays  its  eggs 
under  the  crusts.  These  may  hatch  in  a  short  time  into  immature 
forms  which  shed  their  skin  several  times  before  reaching 
maturity. 

Control. — The  mites  appear  to  spread  very  slowly,  both  from 
infested  regions  to  healthy  tissue  and  to  other  animals  in  the  flock. 
In  an  infested  flock,  only  2  to  3  percent  of  the  sheep  are  attacked. 
The  remedies  proposed  for  common  sheep  scab  mite  may  be  used  to 
combat  the  foot  scab  mite. 

DIPPING  SHEEP 

By  far  the  most  effective  method  of  combating  external  pests 
of  sheep  consists  in  immersing  the  infested  sheep  in  watery  mix- 
tures which  will  kill  the  parasites.     Immersing  sheep  in  a  reliable 


78  OHIO  EXPERIMENT  STATION:  BULLETIN  356 

sheep  dip,  properly  mixed  and  intelligently  handled,  is  cheap,  quick 
and  effective  and  is  the  method  in  general  use  in  this  country. 

The  dip  used  and  the  methods  of  applying  it  vary  in  different 
parts  of  the  country.  For  small  flocks,  a  tub  or  vat  large  enough  to 
hold  a  sufficient  amount  of  the  solution  to  completely  immerse  the 
sheep,  may  be  used.  The  required  amount  of  water  may  be  heated 
in  one  or  two  capacious  kettles.  Where  hundreds  of  sheep  are  to  be 
treated,  especially  prepared  dipping  pens,  vats  and  draining  pens 
and  large  boilers  for  heating  the  water  are  necessary. 

Effective  dips  contain  certain  ingredients  which  are  poisonous 
to  the  parasite.  These  ingredients  may  also,  if  used  in  too  concen- 
trated a  solution,  be  poisonous  to  the  sheep.  But  this  danger  may 
be  avoided  by  preparing  the  dip  as  directed  by  the  manufacturer 
and  maintaining  the  recommended  strength  throughout  the  dipping 
operations.  In  addition  to  the  poisonous  constituent,  the  dip  may 
contain  other  elements,  as  water  to  dilute  and  dissolve  the  poison ; 
also  such  substances  as  alum  or  potash  to  make  the  poison  more 
readily  soluble  or  miscible  with  water. 

The  chief  poisons  used  in  the  various  dips  are  tobacco,  arsenic, 
sulphur  and  lime,  coal-tar  oils  and  cresylic  acid.  Any  one  of  the 
dips  containing  these  poisons,  when  correctly  made,  intelligently 
diluted  and  properly  applied,  is  effective.  Each  has  its  advantages 
and  disadvantages.  For  scab,  lime-sulphur,  tobacco  and  arsenic 
dips  are  usually  recommended.  For  lice  and  the  so-called  sheep 
ticks,  tobacco,  coal-tar  creosote  and  cresylic  acid  dips  are  commonly 
recommended. 

COAL-TAR  CREOSOTE  DIPS 

The  coal-tar  creosote  dips  appear  on  the  market  under  a  be- 
wildering number  of  trade  names.  They  are  made  from  coal-tar 
derivatives.  Creosote  oil  is  the  name  given  to  the  principal  ingre- 
dient. This  oil  is  made  soluble  or  miscible  in  water  by  means  of 
soap. 

Chemists  of  the  U.  S.  Department  of  Agriculture  have  deter- 
mined that  in  order  to  be  effective,  these  dips  should  contain,  when 
diluted  and  ready  for  use,  not  less  than  1  percent  by  weight  of  coal- 
tar  oils  and  cresylic  acid  combined.  In  no  case  should  the  diluted 
dip  contain  more  than  four-tenths  of  1  percent  nor  less  than  bife- 
tenth  of  1  percent  of  the  cresylic  acid ;  but  when  the  proportion  of 
cresylic  acid  falls  below  two-tenths  of  1  percent,  the  coal-tar  oils 
should  be  increased  sufficiently  to  bring  the  total  of  the  coal-tar  and 
the  cresylic  acid  in  the  diluted  dip  up  to  1.2  percent  by  weight. 

Lack  of  a  practical  field  test  for  determining  the  extent  of 
deterioration  of  the  coal-tar  creosote  dips  makes  the  task  of  re- 


SOME  PESTS  OF  OHIO  SHEEP  79 

plenishing  the  dip  in  the  vat  largely  a  matter  of  guesswork.  In 
order  to  obtain  a  homogeneous  solution  of  the  diluted  dip,  it  is  nec- 
essary to  use  soft  water,  and  to  be  sure  that  the  undiluted  dip  is 
homogeneous  in  character  (before  using  it)  as  occasionally,  espec- 
ially in  cold  weather,  a  separation  of  the  coal-tar  oils  and  other  con- 
stituents of  the  dip  may  occur. 

CRESOL  DIPS 

The  cresol  dips  are  made  of  cresylic  acid  and  soap  and  are  sold 
under  various  trade  names.  The  term  cresylic  acid  is  usually  ap- 
plied to  those  cresols  and  phenols,  derived  from  coal-tar,  which  boil 
between  185  degrees  C.  (365  degrees  F.)  and  250  degrees  C.  (482 
degrees  F.).  To  be  effective,  these  dips  should  when  diluted  con- 
tain one-half  of  1  percent  of  cresylic  acid.  At  present  there  is  no 
field  test  for  the  cresol  dips  so  that  renewal  in  the  vat  is,  as  with  the 
coal-tar  creosote  dips,  largely  a  matter  of  guess  work. 

Soft  water  is  essential  to  the  effectiveness  of  these  dips.  In 
fact  it  is  advisable  to  test  the  water  that  is  to  be  used  in  order  to 
avoid  injury  to  the  animals.  This  may  be  done  by  first  thoroughly 
mixing  a  small  portion  of  the  dip  with  water  in  a  bottle  in  the  pro- 
portions recommended  for  dipping.  After  an  interval  of  an  hour  if 
oil  globules  appear  at  the  top  or  bottom  of  the  solution  then  the 
water  is  unfit  for  use. 

NICOTINE  DIPS 

Nicotine  dips  are  sold  under  various  trade  names.  In  using 
this  type  of  dip,  as  with  all  other  commercial  dips,  the  directions  of 
the  manufacturers  should  be  followed.  By  means  of  a  field  test  de- 
signed by  one  of  the  large  manufacturers  the  percentage  of  nicotine 
may  be  ascertained  at  any  time  during  the  dipping  operations. 

LIME- SULPHUR  DIPS 

The  home-boiled  lime-sulphur  dip  is  made  in  the  following  pro- 
portions : 

Lime,  unslacked  8  pounds 

Or  lime,   commercial  hydrated                        11  pounds 

Flowers  of  sulphur  24  pounds 

Water  100  gallons 

The  lime  and  the  sulphur  and  about  30  gallons  of  water  are 
boiled  together  for  1  hour  or  until  all  the  sulphur  disappears  from 
the  surface  of  the  liquid.  This  is  done  in  a  kettle  over  fire  or  in  a 
barrel  or  other  suitable  tank  by  means  of  steam.  The  dip  should 
be  siphoned  or  poured  off  carefully,  and  strained,  then  diluted  to 
100  gallons  and  is  then  ready  for  use.  It  is  necessary  that  suffi- 
cient lime  be  used  to  properly  "cut"  the  sulphur.  On  the  other 
hand  an  excess  of  lime  in  the  dip  will  tend  to  injure  the  sheep  and 
wool. 


Gaylord  Bros. 

Makers 

Syracuse,  N.  Y. 

PAT.  JAN.  21,  1908 


,       JL 


I &&©-_ 


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-BIO    OGY 

LIBRARY 

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*96'1.< 


BIOLOGY 

L'.DRARY 

UNIVERSITY  OF  CALIFORNIA  UBRARY 


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